# Number Needed To Treat Calculator

The number needed to treat is the number of patients needed to be treated to prevent one bad outcome. A negative number needed to treat explains that the treatment has a harmful effect. If the value of NNT is higher then there is no effect in the treatment. Enter the value of control group, events per patients in a year, an experimental group in the NNT calculator. The number needed to treat calculator finds the number of patients needed to be treated.

The number needed to treat is the number of patients needed to be treated to prevent one bad outcome. A negative number needed to treat explains that the treatment has a harmful effect. If the value of NNT is higher then there is no effect in the treatment. Enter the value of control group, events per patients in a year, an experimental group in the NNT calculator. The number needed to treat calculator finds the number of patients needed to be treated.

Code to add this calci to your website

#### Formula:

R_{0} = 1 - e^{(- x / t)}
R_{1} = 1 - e^{(- y / t)}
ARR = R_{0} - R_{1}
Number Needed to Treat (NNT) = 1 / ARR
**Where,**
x = Control Group
y = Experimental Group
t = Event per Patients in Year
ARR = Absolute Risk Reduction
The NNT is useful to understand the harm and benefit of the treatment. Enter the required values and click calculate, the number needed to treat calculator finds the NNT value within seconds.

**Note :**This statistics calculator is presented for your own personal use and is to be used as a guide only. Medical and other decisions should NOT be based on the results of this calculator. Although this calculator has been tested, we cannot guarantee the accuracy of its calculations or results.